String.prototype.replace() 有问题吗？ [复制]

Question

考虑以下sn-p，

console.log('A B'.replace('A', "$'"))

我希望输出是：$' B

但实际输出： B B

有人可以解释这种行为吗？

Answer 1

$ 表示替换字符串中的placeholder：

Pattern	Inserts
$$	Inserts a "$".
$&	Inserts the matched substring.
$`	Inserts the portion of the string that precedes the matched substring.
$'	Inserts the portion of the string that follows the matched substring.
$<em>n</em>	Where n is a positive integer less than 100, inserts the nth parenthesized submatch string, provided the first argument was a RegExp object. Note that this is 1-indexed. If a group n is not present (e.g., if group is 3), it will be replaced as a literal (e.g., $3).
$&lt;Name&gt;	Where Name is a capturing group name. If the group is not in the match, or not in the regular expression, or if a string was passed as the first argument to replace instead of a regular expression, this resolves to a literal (e.g., $&lt;Name&gt;). Only available in browser versions supporting named capturing groups.

Answer 2

根据 MDN 文档和 cmets 中的引用：

$' 插入匹配子串之后的字符串部分。